1. Technical Field
The present invention generally relates to display technology fields and, particularly to a gate output control method.
2. Description of the Related Art
Liquid crystal displays (LCD) have the advantages of high image quality, small size, light weight and a broad application range, and thus are widely applied on consumer electronic products such as mobile phones, notebook computers, desktop displays and televisions, and have gradually replaced the traditional cathode ray tube (CRT) displays as the main trend in the display industry.
Referring to FIG. 1, a structural block diagram of a liquid crystal display associated with the prior art is shown. As illustrated in FIG. 1, the liquid crystal display 100 includes a display substrate 110, a printed circuit board 120 and multiple flexible circuit boards 130. The display substrate 110 has multiple integrated gate driver circuits GD1, GD2 and multiple integrated source driver circuits (not shown in FIG. 1) disposed thereon. The display substrate 110 further has multiple display blocks 111, 112 defined thereon. The integrated gate driver circuits GD1, GD2 respectively control the display blocks 111, 112 and are electrically coupled with each other in series through wire-on-array (WOA) lines. The printed circuit board 120 is electrically coupled with the display substrate 110 through the flexible circuit boards 130 and has a timing controller 121 and a gate pulse modulator 123 disposed thereon. The timing controller 121 is for supplying a gate output enable signal YOE to the integrated gate driver circuits GD1, GD2 and outputting a gate control signal VGH (i.e., generally gate on voltage) and an angling control signal YV1C to the gate pulse modulator 123. The provision of the gate pulse modulator 123 is for reducing the image flicker phenomenon of the liquid crystal display.
Referring to FIG. 2 and FIG. 1 together, FIG. 2 showing a circuit block diagram of the gate pulse modulator 123. As illustrated in FIG. 2, the gate pulse modulator 123 primarily includes an inverter, a level shifter and transistors P1, N1. The angling control signal YV1C is processed by the inverter and the level shifter and thereafter controls the on/off states of the transistors P1, N1 to angling modulate the gate control signal VGH, a modulated gate control signal VGG is produced as a result. The modulated gate control signal VGG is sequentially transmitted to the integrated gate driver circuits GD1, GD2 through the flexible circuit boards 130 and the WOA lines, so as to control gate outputs of the integrated gate driver circuits GD1, GD2.
Referring to FIG. 3 and FIG. 1 together, FIG. 3 showing timing diagrams of the gate output enable signal YOE, the angling control signal YV1C and the modulated gate control signal VGG associated with the prior art. As seen from FIG. 3, portions of the angling control signal YV1C and the modulated gate control signal VGG which are corresponding to the integrated gate driver circuit GD1 have identical waveforms with other portions of the angling control YV1C and the modulated gate control signal VGG which are corresponding to the integrated gate driver circuit GD2, an angled voltage of the modulated gate control signal VGG maintains at V1. A high-level cycle of the angling control signal YV1C is T1, a low-level cycle of the angling control signal YV1C is T2, and a duty ratio of the angling control signal YV1C is T1/T2.
Referring to FIG. 4 and FIG. 1 together, since the impedance of the WOA lines is relatively large, which causes waveforms of the modulated gate control signal VGG during being transmitted to the integrated gate driver circuits GD1, GD2 to be varied from wire attenuation, so that a voltage difference ΔV0 exists between a modulated gate control signal VGG1 arrived at the integrated gate driver circuit GD1 and another modulated gate control signal VGG2 arrived at the integrated gate driver circuit GD2. As a result, the display blocks 111, 112 would have different brightness and whereby an H-line occurs, i.e., the drawback of uneven vertical brightness is existed.